Additional information: It looks like the default repository configurations have the correct (new style, with version) key name. I'm just now going through and cleaning up my .rpmnew's and noticed that my repo configurations had such, so that the old repo configs with the old name are used. So probably this only affects people that have modified their repo configs and get .rpmnew's of them as a result.

I got this error message too.
And I simply remove the file /etc/yum.repos.d/fedora-updates-testing.repo and rename /etc/yum.repos.d/fedora-updates-testing.repo.rpmnew file back to replace it.
It works fine now.

(In reply to Truong Anh Tuan from comment #4)
> I got this error message too.
> And I simply remove the file /etc/yum.repos.d/fedora-updates-testing.repo
> and rename /etc/yum.repos.d/fedora-updates-testing.repo.rpmnew file back to
> replace it.
>
> It works fine now.
I had the same problem, but it was the fedora-updates.repo that had a rpmnew file.
Replacing the fedora-updates.repo with the rpmnew file fixed it.